Sandberg was pregnant with her first child and had ballooned to the size of a “whale” (her words, not mine). Late for a sales meeting, she was only able to find a parking spot far from the front door of Google’s headquarters, where she worked before her current job of COO at Facebook, and waddled her way inside. The next day, Sandberg marched in to see her boss, Sergey Brin, and demanded that the company create closer pregnancy parking for expectant mothers. Brin immediately said yes and wondered why such an idea had never occurred to him previously.

Sandberg asked herself the same question:

“As one of Google’s most senior women, didn’t I have a special responsibility to think of this? … The other pregnant women might have suffered in silence, not wanting to ask for special treatment. Or maybe they lacked the confidence or seniority to demand that the problem be fixed. Having one pregnant woman at the top – even one who looked like a whale – made the difference.”

It is this “aha moment” that becomes jumping off point for the powerful argument that is at the heart of Lean In: namely, that the feminist revolution has stalled and that the key to get the ball rolling again is two- fold. First, to ensure that “there are more women in leadership roles giving strong and powerful voice to their needs and concerns”; and second, to encourage women to overcome their own “internal obstacles” to achieving success.

These are laudable goals. That they come from a woman at the top rungs of the corporate ladder – a rarefied locale where writing controversial books about taboo subjects is generally frowned upon – is remarkable.

But as someone who has no chance of being pregnant (and, despite which, is making every effort to avoid being a whale), and who is, in fact, a man, I was struck by something else about Sandberg’s parking lot anecdote. Why didn’t Sergey Brin get this already? And what about Eric Schmidt, who at the time was CEO of Google?

Why should a man be unable to fully appreciate the challenges that face his female employees? After all, every man has a mother; many have a wife or girlfriend; still others have daughters and sisters. Men have friends, confidantes, neighbors and co-workers who are women (some of whom have even gotten pregnant). In the year 2013, when women are as likely as men to graduate from college and enter the workforce, don’t men have a responsibility to understand the challenges facing women in the workplace?

So, as I read Sandberg’s book, I kept asking myself: why are men being let off the hook?

I don’t mean this as a criticism. You need to review the book you read, not the book you wish had been written – and this is a book that is more clearly directed at women. Moreover, to suggest that Sandberg should have paid more attention to men is at pace with the sort of genderexceptionalism that Sandberg explores in the book.

The other reason this isn’t intended to be a disparagement of Lean In is because the book Sandberg has written is lively, entertaining, urgent and yes, even courageous. By shaking the hornet’s nest of gender relations in the workplace, Sandberg has admirably placed a bulls-eye on her back, opening herself up to the charge that she’s a “rabble-rouser in a skirt” at a time when only about one quarter of women even consider themselves a feminist (and I have to think the number of self-described male feminists is much smaller).

At a moment when the new CEO of Yahoo, Marissa Mayer, is dissingfeminism as “too negative” and rejecting the idea that she would define herself by the dreaded “F” word, Sandberg has penned a self-described “sort of” feminist manifesto. And she has done so in manner I didn’t think was possible: Lean In is both a radical read and incredibly accessible.

For women, Sandberg’s workplace tales will be a confirmation of that with which they are all too familiar: of being passed over for promotion; of being penalized for taking time off to raise children; of “leaning back” as Sandberg puts it when faced with the challenge of balancing childrearing with work; of being underpaid compared to male colleagues; of feeling guilt over leaving young children in the care of others; of underestimating one’s skills in comparison to men; of constant fears of seeming either too nice, too aggressive or too ambitious. And the list goes on.

To Sandberg’s credit, she doesn’t simply bemoan these often painful realities that face working women, but offers a constructive set of ideas and tools for breaking these patterns: be honest in the workplace; don’t put on the brakes in your career because you want to have kids; find a partner who will share the burden or childrearing; stop measuring oneself by the decidedly unhelpful “have it all” standard.

Yet, while it’s obvious that women have much to gain from reading Sandberg’s book, so do men – perhaps even more so.

I write those words as someone who considers himself something of an imperfect feminist or perhaps, with a bit more candor, a reformed cad. Reading Lean In, I found myself more than once chastened, even embarrassed, at how prevalent gender stereotypes are in society – and how guilty I’ve been in my own life at perpetuating them.

Lean In tells an important story of gender socialization and how women adhere themselves, often sub-consciously, to traditional female roles, both at work and at home. But of course, there is a flip side: men often fall into the same gender patterns – and in ways we don’t always notice and are all too infrequently reminded of.

One of my favorite stories in Lean In is of a man who proudly tells a group of co-workers that on the day his first child was born, he played soccer with his friends. Sandberg’s husband, who is portrayed in the book as pretty much the perfect spouse, challenges him for putting his own selfish needs above that of his wife and child. Good for him. But how many men would even recognize that such behavior is so extraordinarily thoughtless? How many would speak up?

In Sandberg’s telling, small interventions like these can have a lasting impact. Even the smallest realization of how we abide by antiquated gender stereotypes – and the larger recognition of how we can change our behavior – can make a world of difference.

It was a point reinforced for me years ago when I was heading home from a dinner party and a then girlfriend commented on the fact that when the meal was over, all the women at the table got up to clear the dishes and the men remained seated. I hadn’t noticed, but next time I was at a similar event, I did. Since then, I’ve developed an odd reputation for always cleaning up the dishes at family gatherings.

This is, of course, a minor transformation. But in ways both small and large, it caused me to look at gender roles in a way I simply hadn’t before. I imagine, for many men who read Sandberg’s book, the anecdotes she recounts will open their eyes to realities to which they’ve long been blind.

But of course, it will take more than personal interventions to shift gender norms – and if there is any place where Sandberg’s book is lacking, it is here. Sandberg argues “a truly equal world would be one where women ran half our countries and companies and men ran half our homes.” And she urges the men who read Lean In to play a more active role at home; to take on the childrearing responsibilities and household tasks that so frequently fall on the shoulders of women, whether they work full-time or stay at home with kids. She bemoans male parents who talk about raising kids as a “hobby”, or refer to taking care of their kids as babysitting (no one ever says a woman baby-sits their kids).

This example reminded of my own experience taking care of our young daughter on a Saturday afternoon, when my wife had to work – and calling it ” daddy daycare”. Actually, it’s called being a father.

But while Sandberg makes a persuasive argument that women need to play a more leading role in their own professional development, men must clearly lean in as well – and they must do it in the workplace. As Sandberg makes clear at the outset, it is men who run the country; men who get the CEO jobs; men who rise fastest up the corporate ladder; and men who often make the decisions that directly affect women in the workplace. It’s simply not enough to expect women to carry the heavy load, because focusing on only one side of the ledger won’t bring about the type of systemic change in workplace gender roles that is needed.

Men need to recognize their own responsibility. Though Lean In has only been out a few days, that impact is already being seen. John Chambers, the CEO of Cisco recently sent an internal email to his employees urging them to read Sandberg’s book in the hopes that it would open their eyes to workplace discrimination in the same way it did for him:

“While I have always considered myself sensitive to and effective on gender issues in the workplace, my eyes were opened in new ways and I feel a renewed sense of urgency to make the progress we haven’t made in the last decade. After reading Lean In and listening to Sheryl, I realize that, while I believe I am relatively enlightened, I have not consistently walked the talk.”

In the end, men have much to gain from such a change in attitude. Let’s put aside the obvious benefits to a company’s bottom line, or the happiness of its workforce, or the efficiency of its operations when women feel they are equal players (and beneficiaries) in their enterprise’s success. Men have much to gain because they too are often trapped in gender stereotypes that limit their personal and professional options.

We tend to think that it is women who must juggle the challenges of raising a family and being successful at their job. But what about the man who works 60-70 hours a week, is always on the road and never sees his kids? Is the societal expectation that he is to be the family breadwinner trapping him in a job he hates and a life he finds unfulfilling? Or what about the male executive who would rather slow down and spend more time at home, but knows that to do so risks undermining their own career development? Or perhaps there is the new father who would just as soon get out of the rat race and raise his children, but fears the social stigma of being a stay-at-home dad?

This doesn’t mean that the workplace challenges facing men and women are equivalent. But it is foolish to ignore the constraints on men as well. As Sandberg perceptively points out:

“If we make it too easy for women to drop out of the career marathon, we also make it too hard for men. Just as women feel that they bear the primary responsibility of supporting their families financially. Their self-worth is tied mainly to their professional success, and they frequently believe that they have no choice but to finish that marathon.”

These are smart words. Hell, they might actually make for a pretty good second book.

They are but one small example of the unexpected achievement that is Lean In. Sheryl Sandberg has put her finger on something that is all too rarely discussed in a culture that views women’s issues as a discrete subject that only affects half the population – and that can be remedied with laws mandating equal pay, paid family and sick leave, affordable child and flexible work schedules. Of course, we do need all of these, but the questions that Sandberg is exploring run deeper: how we work, how we raise children and how we make the difficult life choices that seek to balance these two issues.

Lean In is the beginning of an important and long-overdue conversation in the United States – but it will only be a national conversation, and one that endures, if men do their part and lean in, too.